From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/smb/client/namespace.c | 298 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 298 insertions(+) create mode 100644 fs/smb/client/namespace.c (limited to 'fs/smb/client/namespace.c') diff --git a/fs/smb/client/namespace.c b/fs/smb/client/namespace.c new file mode 100644 index 000000000..52a51b032 --- /dev/null +++ b/fs/smb/client/namespace.c @@ -0,0 +1,298 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Contains mounting routines used for handling traversal via SMB junctions. + * + * Copyright (c) 2007 Igor Mammedov + * Copyright (C) International Business Machines Corp., 2008 + * Author(s): Igor Mammedov (niallain@gmail.com) + * Steve French (sfrench@us.ibm.com) + * Copyright (c) 2023 Paulo Alcantara + */ + +#include +#include +#include +#include +#include +#include +#include +#include "cifsglob.h" +#include "cifsproto.h" +#include "cifsfs.h" +#include "cifs_debug.h" +#include "fs_context.h" + +static LIST_HEAD(cifs_automount_list); + +static void cifs_expire_automounts(struct work_struct *work); +static DECLARE_DELAYED_WORK(cifs_automount_task, + cifs_expire_automounts); +static int cifs_mountpoint_expiry_timeout = 500 * HZ; + +static void cifs_expire_automounts(struct work_struct *work) +{ + struct list_head *list = &cifs_automount_list; + + mark_mounts_for_expiry(list); + if (!list_empty(list)) + schedule_delayed_work(&cifs_automount_task, + cifs_mountpoint_expiry_timeout); +} + +void cifs_release_automount_timer(void) +{ + if (WARN_ON(!list_empty(&cifs_automount_list))) + return; + cancel_delayed_work_sync(&cifs_automount_task); +} + +/** + * cifs_build_devname - build a devicename from a UNC and optional prepath + * @nodename: pointer to UNC string + * @prepath: pointer to prefixpath (or NULL if there isn't one) + * + * Build a new cifs devicename after chasing a DFS referral. Allocate a buffer + * big enough to hold the final thing. Copy the UNC from the nodename, and + * concatenate the prepath onto the end of it if there is one. + * + * Returns pointer to the built string, or a ERR_PTR. Caller is responsible + * for freeing the returned string. + */ +char * +cifs_build_devname(char *nodename, const char *prepath) +{ + size_t pplen; + size_t unclen; + char *dev; + char *pos; + + /* skip over any preceding delimiters */ + nodename += strspn(nodename, "\\"); + if (!*nodename) + return ERR_PTR(-EINVAL); + + /* get length of UNC and set pos to last char */ + unclen = strlen(nodename); + pos = nodename + unclen - 1; + + /* trim off any trailing delimiters */ + while (*pos == '\\') { + --pos; + --unclen; + } + + /* allocate a buffer: + * +2 for preceding "//" + * +1 for delimiter between UNC and prepath + * +1 for trailing NULL + */ + pplen = prepath ? strlen(prepath) : 0; + dev = kmalloc(2 + unclen + 1 + pplen + 1, GFP_KERNEL); + if (!dev) + return ERR_PTR(-ENOMEM); + + pos = dev; + /* add the initial "//" */ + *pos = '/'; + ++pos; + *pos = '/'; + ++pos; + + /* copy in the UNC portion from referral */ + memcpy(pos, nodename, unclen); + pos += unclen; + + /* copy the prefixpath remainder (if there is one) */ + if (pplen) { + *pos = '/'; + ++pos; + memcpy(pos, prepath, pplen); + pos += pplen; + } + + /* NULL terminator */ + *pos = '\0'; + + convert_delimiter(dev, '/'); + return dev; +} + +static bool is_dfs_mount(struct dentry *dentry) +{ + struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb); + struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb); + bool ret; + + spin_lock(&tcon->tc_lock); + ret = !!tcon->origin_fullpath; + spin_unlock(&tcon->tc_lock); + return ret; +} + +/* Return full path out of a dentry set for automount */ +static char *automount_fullpath(struct dentry *dentry, void *page) +{ + struct cifs_sb_info *cifs_sb = CIFS_SB(dentry->d_sb); + struct cifs_tcon *tcon = cifs_sb_master_tcon(cifs_sb); + size_t len; + char *s; + + spin_lock(&tcon->tc_lock); + if (!tcon->origin_fullpath) { + spin_unlock(&tcon->tc_lock); + return build_path_from_dentry_optional_prefix(dentry, + page, + true); + } + spin_unlock(&tcon->tc_lock); + + if (unlikely(!page)) + return ERR_PTR(-ENOMEM); + + s = dentry_path_raw(dentry, page, PATH_MAX); + if (IS_ERR(s)) + return s; + /* for root, we want "" */ + if (!s[1]) + s++; + + spin_lock(&tcon->tc_lock); + len = strlen(tcon->origin_fullpath); + if (s < (char *)page + len) { + spin_unlock(&tcon->tc_lock); + return ERR_PTR(-ENAMETOOLONG); + } + + s -= len; + memcpy(s, tcon->origin_fullpath, len); + spin_unlock(&tcon->tc_lock); + convert_delimiter(s, '/'); + + return s; +} + +static void fs_context_set_ids(struct smb3_fs_context *ctx) +{ + kuid_t uid = current_fsuid(); + kgid_t gid = current_fsgid(); + + if (ctx->multiuser) { + if (!ctx->uid_specified) + ctx->linux_uid = uid; + if (!ctx->gid_specified) + ctx->linux_gid = gid; + } + if (!ctx->cruid_specified) + ctx->cred_uid = uid; +} + +/* + * Create a vfsmount that we can automount + */ +static struct vfsmount *cifs_do_automount(struct path *path) +{ + int rc; + struct dentry *mntpt = path->dentry; + struct fs_context *fc; + void *page = NULL; + struct smb3_fs_context *ctx, *cur_ctx; + struct smb3_fs_context tmp; + char *full_path; + struct vfsmount *mnt; + struct cifs_sb_info *mntpt_sb; + struct cifs_ses *ses; + + if (IS_ROOT(mntpt)) + return ERR_PTR(-ESTALE); + + mntpt_sb = CIFS_SB(mntpt->d_sb); + ses = cifs_sb_master_tcon(mntpt_sb)->ses; + cur_ctx = mntpt_sb->ctx; + + /* + * At this point, the root session should be in the mntpt sb. We should + * bring the sb context passwords in sync with the root session's + * passwords. This would help prevent unnecessary retries and password + * swaps for automounts. + */ + mutex_lock(&ses->session_mutex); + rc = smb3_sync_session_ctx_passwords(mntpt_sb, ses); + mutex_unlock(&ses->session_mutex); + + if (rc) + return ERR_PTR(rc); + + fc = fs_context_for_submount(path->mnt->mnt_sb->s_type, mntpt); + if (IS_ERR(fc)) + return ERR_CAST(fc); + + ctx = smb3_fc2context(fc); + + page = alloc_dentry_path(); + full_path = automount_fullpath(mntpt, page); + if (IS_ERR(full_path)) { + mnt = ERR_CAST(full_path); + goto out; + } + + tmp = *cur_ctx; + tmp.source = NULL; + tmp.leaf_fullpath = NULL; + tmp.UNC = tmp.prepath = NULL; + tmp.dfs_root_ses = NULL; + fs_context_set_ids(&tmp); + + rc = smb3_fs_context_dup(ctx, &tmp); + if (rc) { + mnt = ERR_PTR(rc); + goto out; + } + + rc = smb3_parse_devname(full_path, ctx); + if (rc) { + mnt = ERR_PTR(rc); + goto out; + } + + ctx->source = smb3_fs_context_fullpath(ctx, '/'); + if (IS_ERR(ctx->source)) { + mnt = ERR_CAST(ctx->source); + ctx->source = NULL; + goto out; + } + ctx->dfs_automount = ctx->dfs_conn = is_dfs_mount(mntpt); + cifs_dbg(FYI, "%s: ctx: source=%s UNC=%s prepath=%s dfs_automount=%d\n", + __func__, ctx->source, ctx->UNC, ctx->prepath, ctx->dfs_automount); + + mnt = fc_mount(fc); +out: + put_fs_context(fc); + free_dentry_path(page); + return mnt; +} + +/* + * Attempt to automount the referral + */ +struct vfsmount *cifs_d_automount(struct path *path) +{ + struct vfsmount *newmnt; + + cifs_dbg(FYI, "%s: %pd\n", __func__, path->dentry); + + newmnt = cifs_do_automount(path); + if (IS_ERR(newmnt)) { + cifs_dbg(FYI, "leaving %s [automount failed]\n" , __func__); + return newmnt; + } + + mnt_set_expiry(newmnt, &cifs_automount_list); + schedule_delayed_work(&cifs_automount_task, + cifs_mountpoint_expiry_timeout); + cifs_dbg(FYI, "leaving %s [ok]\n" , __func__); + return newmnt; +} + +const struct inode_operations cifs_namespace_inode_operations = { + .fileattr_get = cifs_fileattr_get, +}; -- cgit v1.3.1